A random sample of 18 purchases showed the amounts in the table (in $). The mean is $46.50 and the standard deviation is $25.12. 40.29 20.34 40.35 2.680 3.24 61.79 82.02 24.90 a) How many degrees of freedom does the t-statistic have? b) How many degrees of freedom would the t-statistic have if the sample size had been 2? 26.41 26.97 84.17 53.72 53.85 74.51 74.67 49.17 61.14 56.77 degrees of freedom. a) The t-statistic has (Simplity your answer.) b) If the sample size had been 2, the t-statistic would have degrees of freedom. (Simplify your answer.)